ms/http_enable_handler is a SAP Parameter attribute which is used to control Enable/disable HTTP handler routines called by message server information. This is available within R/3 SAP systems depending on the version and release level.
Below is the standard documentation available and a few details of the attributes values .
This parameter can have the following values:
1 : HTTP request handler in ICF is to be called
0 : HTTP request handler in ICF is not to be called
The message server calls a number of HTTP request handlers in the
ICF to collect information about HTTP load balancing and the
distribution of HTTP requests.
To do this, it sends a URL which contains
/default_host/sap/public/icf_info/urlprefix or logon_groups
to an application server.
If an HTTP request handler does not exist or has errors, it is
marked as having errors.
If this HTTP request handler is to be called again later, this
parameter must be dynamically set to 1 again.
See SAP Parameter Documentation for full SAP documentation for this profile parameter.